TCP Bandwidth or Mb per Minute

James Suttles

Active Member
Anyone know the amount of bandwidth that a TCP base / Rover Session takes. I would think the usage would be symmetrical, so if we know one end, the other end should be the same. I am working on a solution where GSM cell coverage is not available and radio will not reach the rover. I am looking at Satellite phone / hotspot. The firm I am looking at
http://www.groundcontrol.com/IsatHub.htm#IsatHub_Service charges for the service by Megabytes per month. So I kinda need to know the amount of bandwidth, to figure how much time the monthly service would allow.

Thx
 

James Suttles

Active Member
I found this in a RTCM 3.0 (Power Point), on the web.... does this help or are we looking at more variables?

● Bandwidth Requirement (10 SVs, MT 1004) – 1368 Bits (171 Bytes) per Epoch ● Maximum Data Rate: 1000 Hz

If this is true, should the math be 1,000,000 (MB) / 171 (bytes) / 60 (1hz or 1 second) = minutes or did I miss a step. I know we are upsampling the 5hz, so I would assume the data stream is 1hz.
 

James Suttles

Active Member
If that calculation is correct, a 50MB plan should yield 81 hours of service. Anyone have anyway to tell if this is correct?
 

Matt Johnson

Well-Known Member
5PLS
The answer depends on the number satellites, transmission rate and the format of the messages. I think 2000 bts or 0.9 MB / hour is a safe estimate GPS + GLONASS at 1 Hz with RTCM 3.0 Min format. You can always check the data use by checking the total data used by your existing hotspot before and after a session.
 

James Suttles

Active Member
So with that estimate, and which makes sense, considering the info I had gathered, looked to be GPS only, no GLONASS, 0.9MB/Hour would work to about 55 hours on a 50MB plan, which according to the aforementioned site, would be roughly $100 per month. Not too bad, if you got an area you cannot reach via radio, or GSM cell coverage. Definitely worth considering if it works. Plus looks like incoming call to a $10 per month number, are free.

Thanks for helping figure out an estimate of how many MB's per hour.
 

James Suttles

Active Member
What kind of distance would a cell repeater give you, On a large wildlife boundary, of 5000 acres the cell coverage stops at the edge of the area. The radio will reach partly into it. Its heavy woods, so moving the base to another location is too heavy in vegetation, so was trying to figure out how to get RTK, when all other forms on communiation are not available. I can alway PPK the points, but prefer to have real time data.
 

Shawn Billings

Shawn Billings
5PLS
A bridge might be a good alternative. The JLink with battery and an internal 1-watt UHF radio would allow you to receive cellular and transmit UHF. There are other more powerful versions too, 35-watt and a 4-watt. The 1-watt is small and portable. I think the cost would be around $2500, but I've never really configured one, so that is subject to change depending on needed options.
 

Ryan

New Member
Anyone know the amount of bandwidth that a TCP base / Rover Session takes. I would think the usage would be symmetrical, so if we know one end, the other end should be the same. I am working on a solution where GSM cell coverage is not available and radio will not reach the rover. I am looking at Satellite phone / hotspot. The firm I am looking at
http://www.groundcontrol.com/IsatHub.htm#IsatHub_Service charges for the service by Megabytes per month. So I kinda need to know the amount of bandwidth, to figure how much time the monthly service would allow.

Thx
Why not just a 35 watt radio?
 

Adam

Well-Known Member
5PLS
Ive been where Doug is working and even the radio is no help. Miles and Miles of mountains and forests. Actually I can see the south side of it from where I'm standing on the farm. See the distant Mountain.
15491470242391897243956.jpg
 

Adam

Well-Known Member
5PLS
A bridge might be a good alternative. The JLink with battery and an internal 1-watt UHF radio would allow you to receive cellular and transmit UHF. There are other more powerful versions too, 35-watt and a 4-watt. The 1-watt is small and portable. I think the cost would be around $2500, but I've never really configured one, so that is subject to change depending on needed options.
Doug is FHSS.
 

Adam

Well-Known Member
5PLS
From what I see on the radio page of the website the JLink radio is available with a 1watt FHSS radio Doug. Range from the radio would be about the same as you see with your LS when using FHSS.
 

Adam

Well-Known Member
5PLS
What kind of range, do you think we are talking about with the Jlink?
Do you have a place to even put a base that has cell service within a couple of miles of your site? I know the times I've been up there that cell service goes to pot well before you ever get to any parking or open areas.
 

James Suttles

Active Member
Hmmmmm, so not really an option. The SAT Hotspot, provides 458Kbps of bandwidth, which should be plenty for a RTK stream, correct? $100 per month will get you around 50 hours of RTK, in areas where no cell signal or Radio will reach. You have to aim the SAT Hotspot, (which is an external device) so I would think you would fire up the SAT Hotspot, point it, collect your RTK shot, and then power down the SAT HotSpot till you get to the next point. If you are staking the point out, this solution probably would not work. Too bad the Javad doesn't accept a SAT sim card, from BGAN Satellite Network, That would make things extremely easy. Some of their plans are simply pay for what you use, so cost could be less and if you do not use it, you are not paying for service you are not using.

Could that be added to the wish list, the capability of a BGAN sim card, and an external antenna, for it, etc.
 

James Suttles

Active Member
Adam, I do have some limited coverage on the front side of the mountain, and on top of a peak @ 3000ft. It does look into the Wildlife area, but there are some deep ravines that will probably not be reached by the radio at all. Those we may have to break out the total station, or PPK them. The area is like 12000 acres, so its a lot area.
 

James Suttles

Active Member
I think Adam will back up that 35w radio, will not reach. The terrain is very mountainous, with some relief as much as 1800ft, and a radio will not shoot through a mountain. We have some 450mhz two way radios pushing 50w and they will not reach some of the area. So I was just trying to find a solution that works in almost any environment. I think in any other terrain, say flat with vegetation as your only obstruction, that a 35W radio, would fit almost all situations.
 
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